The phenomenon of nuclear magnetic resonance (NMR) has been used as an analytical tool in science and medicine for some time. Generally speaking, NMR is sensitive to a wide range of chemical and physical properties of objects of analytical study, such as animate and inanimate subjects, and may be made sensitive to spatial position of such objects as well. As such, NMR technology, such as NMR principles, methods, and/or apparatus, may be used in a variety of applications. By way of example, an NMR apparatus may be used in an analytical chemistry application, in which the apparatus may be used to determine the chemical composition of a sample material. Further by way of example, an NMR apparatus may be used in a medical imaging application, in which the apparatus, such as a magnetic resonance imaging (MRI) scanner, for example, may be used to view structures inside an intact human. Still further by way of example, NMR technology may be useful for studying any of a variety of or combination of properties, such as the structure of a solid or a semi-solid, temperature, pressure, elasticity, velocity, and/or any of other static or dynamic physical properties. Data from NMR studies, such as that concerning chemical and/or physical properties of an object of study, may be integrated together and/or integrated with data from MRI studies. A “functional MRI” study of localized brain activity is merely one example of such an integration of data.
Generally, functional roles of various components of different NMR apparatus have been developed to varying degrees. In the case of an NMR spectrometer, for example, such roles have been fairly well established. In most NMR technology, a source of magnetic field is used to bring about the NMR phenomenon. The source may be a superconducting electromagnet (such as that often used in modern NMR and MRI instruments), non-superconducting electromagnets, such as iron-core and/or air-core electromagnets, for example, or permanent magnets. An NMR magnet generally has a region over which its field, or the intensity thereof, is substantially uniform or homogeneous, such as at least 100 parts per million (ppm) for a magnet used in an MRI application and perhaps as high as 1 part per billion (ppb) for a magnet used in an analytical chemistry NMR application, by way of example. Lower degrees of uniformity or homogeneity can often be adequate for useful measurement in various applications. A single coil or microcoil (see, for example, T. L. Peck, et al., Design and Analysis of Microcoils for NMR Microscopy, J. Magn. Reson. B108 (1995), pp. 114-124) may be placed inside the region of the substantially homogeneous field and the object or sample of study, such as a sample material sample, for example, may be held inside the coil. The coil may be a solenoid, a saddle-coil, a surface coil, or any other structure capable of coupling to the sample magnetically. While some coils are helical in shape, a useful coil may be helical or non-helical in shape.
Various suitable NMR electronic components, such as transmit and receive circuitry (which may be combined into a single “transceiver” unit), for example, may be coupled to the coil to excite magnetic resonance in the sample and to detect a signal, such as a voltage signal, for example, that the magnetic resonance in the sample creates in the coil. The excitation input may be radio-frequency (rf) energy or power, such as a short burst or a series of pulses of rf energy or power, the duration of which may be many orders of magnitude shorter than the duration of the magnetic resonance signal coming from the sample. The transmit and receive circuitry may include various functional components, such as any of a variety of components suitable for modifying or processing the excitation input or modifying or processing (such as amplifying, for example) the signal from the sample. By way of example, an NMR spectrometer may have hardware and/or software components suitable for manipulation of the signal to provide an output meaningful to the recipient of the output, such as a human operator. Further by way of example, an MRI scanner may have components suitable for providing spatial information that is useful for forming images. An NMR apparatus, such as an MRI scantier, for example, may employ more than one independent coil surrounding the sample, wherein one coil is used to excite magnetic resonance in the sample and another coil is used to detect magnetic resonance from the sample. In such a case, the excitation coil may be coupled to transmit circuitry and the detection may be coupled to the receive circuitry of the electronic system employed.
While the functioning of various components of different NMR apparatus have been developed to varying degrees, such as generally described above, the technology used to achieve such roles or such functioning continues to evolve. Development of NMR technology, such as apparatus, applications, methods, and/or the like, is generally desirable.